Consumers' need for more memory on their advanced, Internet-enabled mobile phones is spurring not only a surge in removable flash card slots, but also dramatic changes in the mobile memory landscape itself.

According to a report released last week by Strategy Analytics, removable memory card slots appeared in 53 percent of all mobile phones shipped last year, or 592 million. Thanks to user demand for phones that can support an increasing number of memory-hungry mobile applications, that number is expected to grow 13 percent annually, hitting 1.04 billion by 2011.

"The benefits of being able to upsize your capacity and transfer your data to a new phone make memory card slots an essential requirement for all mid-to-high end phones," Stuart Robinson, director of Strategy Analytics' Handset Component Technologies service, told InternetNews.com.

At the same time, increasing demands on phone memory are also likely to spur the growth of more advanced memory types, the report found.

"In the high-end phones, the memory is wanted for office applications such as e-mail and file storage for office applications," Robinson told InternetNews.com in an e-mail.

To help meet those needs, memory vendor SanDisk earlier this year announced it was developing a 12 gigabyte (GB) microSDHC card -- a 50 percent boost in card capacity over its existing line. According to the company, it can store a combination of 1,500 songs, 3,600 photos and 24.5 hours of video.

"People are using phones for video, music, maps, games -- and all these applications require memory," Rachel Polish, senior public relations manager at SanDisk, told InternetNews.com. Many new multimedia phones have a number of bells and whistles and without enough storage capacity it will be difficult to use these phones to their fullest potential.

Along with pushing memory makers to add more capacity and phone makers to roll out more devices with memory slots, users' increasing need for more phone memory is also spurring changes in memory card technology.

The MultiMediaCard (MMC) format, a flash memory standard introduced in the late 1990s, has been eclipsed by microSD (Secure Digital) and microSDHC (Secure Digital High Capacity) slot formats, which together now appear in 57 percent of slotted phones.

Just about every new phone now supports either microSD or microSDHC cards, Robinson said.

"Even Sony Ericsson has begun using microSD in favor of its own Memory Stick Micro format," he said.

That's because card formats increasingly will compete on read/write transfer speeds, rather than memory capacity, as files get bigger and the time necessary to retrieve or save a file becomes a point of differentiation, Robinson said.

UFS is designed as a high-capacity, high-speed option to microSD, and is being developed by a group of vendors players including Nokia, Samsung and Sony Ericsson.

While the new card standard isn't expected to arrive until 2009, the specification could bring higher data transfer speeds as well as increased reliability in flash memory storage.

"The goal of UFS is to increase speeds by an order of magnitude within the next few years, but SanDisk is planning higher-speed versions of its cards, too, so UFS will need another unique selling point," Robinson said.

Regardless of the format, Robinson said manufacturers will continue to add memory slots directly into their devices, since the cost of memory cards can be offloaded onto users. Embedded memory, on the other hand, is a direct cost to the manufacturer.

For instance, microSD cards enable users to easily move data between phones or among different devices entirely. In addition to phones, they can be used in handheld GPS devices, portable media players, digital audio players, video game consoles and expandable USB flash memory drives.

"Content can be transferred more easily from one phone to another when upgrading, and the memory capacity of the phone can be increased more easily with removable cards," Robinson said.

"The more applications customers use on their cell phone, the more memory they need," Jeff Kagan, wireless and telecom industry analyst, told InternetNews.com. "As we continue to do more with our cell phones, these cards will become increasingly important."